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authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2013-07-23 17:23:54 +0000
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-08-20 10:25:35 -0400
commitee0726407feaf504dff304fb603652fb2d778b42 (patch)
tree408473642b805ba2e56b94766f877fcb8518f24b /drivers/xen
parent072b2064b88f709c53a83c6ec1f1cb17bf7c0abf (diff)
xen/m2p: use GNTTABOP_unmap_and_replace to reinstate the original mapping
GNTTABOP_unmap_grant_ref unmaps a grant and replaces it with a 0 mapping instead of reinstating the original mapping. Doing so separately would be racy. To unmap a grant and reinstate the original mapping atomically we use GNTTABOP_unmap_and_replace. GNTTABOP_unmap_and_replace doesn't work with GNTMAP_contains_pte, so don't use it for kmaps. GNTTABOP_unmap_and_replace zeroes the mapping passed in new_addr so we have to reinstate it, however that is a per-cpu mapping only used for balloon scratch pages, so we can be sure that it's not going to be accessed while the mapping is not valid. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> CC: alex@alex.org.uk CC: dcrisan@flexiant.com [v1: Konrad fixed up the conflicts] Conflicts: arch/x86/xen/p2m.c
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/gntdev.c11
1 files changed, 2 insertions, 9 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index eab5427c75f5..e41c79c986ea 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -272,19 +272,12 @@ static int map_grant_pages(struct grant_map *map)
* with find_grant_ptes.
*/
for (i = 0; i < map->count; i++) {
- unsigned level;
unsigned long address = (unsigned long)
pfn_to_kaddr(page_to_pfn(map->pages[i]));
- pte_t *ptep;
- u64 pte_maddr = 0;
BUG_ON(PageHighMem(map->pages[i]));
- ptep = lookup_address(address, &level);
- pte_maddr = arbitrary_virt_to_machine(ptep).maddr;
- gnttab_set_map_op(&map->kmap_ops[i], pte_maddr,
- map->flags |
- GNTMAP_host_map |
- GNTMAP_contains_pte,
+ gnttab_set_map_op(&map->kmap_ops[i], address,
+ map->flags | GNTMAP_host_map,
map->grants[i].ref,
map->grants[i].domid);
}